The present invention relates to bone clamps used in surgical procedures to urge broken bones into alignment for the proper mending thereof, and for the fixing of plates to fractured bones so the plates may be screwed to the bones to maintain proper positioning thereof following reduction or approximation of the fracture.
There are commercially available a variety of bone clamps for reducing bone fractures, i.e. the urging of fractured portions of a bone into proper alignment with one another. These generally fall into two categories which include parallel and perpendicular types, designated in accordance with the orientation of the axis of the device with respect to the axis of the fracture. A parallel bone clamp approaches the axis of the fracture parallel with its own axis. A perpendicular bone clamp approaches the axis of the fracture with its own axis perpendicular to the axis of the fracture.
Included among the more commonly used parallel bone clamps are the Verbrugge, the Lange, the Kern, the Ulrich, the Lambotte, the Seidel, and the Lanenbeck. Each of these clamping devices utilizes a ratchet mechanism to apply and maintain pressure on the severed portions of the bone being urged into mutual contact alignment. Although effective for a variety of applications, the above mentioned bone clamps occupy too much space to be used in the repair of small bone fractures, such are those of the metacarpal and phalanx. In reducing such fractures, the clamp must be oriented with its axis in parallel to the bone fracture and cannot be inserted into the confining wound because of the close proximity of the adjacent metacarpals or metatarsals. Similarly, in repair of fractures to the phalanx, the extensor mechanism greatly impedes insertion of such parallel bone clamps into the wound.
The instrument currently used most often for the repair of small bone fractures is the common towel clip. Deriving its name from its original designed purpose of holding towels together in a sterile field, the towel clip was never intended for use in bone fracture surgery. The towel clip falls into the category of parallel type bone clamps, with its shape resembling a pair of miniature ice tongs having a pair of sharp, opposing points which may be brought together by scissor action. A ratchet mechanism assists in applying and maintaining pressure on a fractured bone interposed between the points. It has found application as a device used in small bone reductions because it occupies less space than most parallel bone clamps, and is commonly available. In addition, its rugged design permits the application of relatively large forces required to reduce bones and the two sharp points reliably grasp the opposed bone surfaces without slipping. There are however two main disadvantages associated with the towel clip. Because the towel clip functions as a parallel bone clamp, it occupies too much space for many smaller procedures. Also, many towel clips have ratchet bars of insufficient length, allowing the ratchet teeth to disengage when the towel clip is open during a bone reduction.
Perpendicular bone clamps currently available include such devises as the Lowman-Gerster and the Lowman-Hoglund bone clamps. Also included is the Bunnell-Howard arthrodesis bone clamp. By permitting insertion thereof into the wound incision perpendicular with the axis of the fracture, such instruments can be used to more effectively than parallel bone clamps in reduction of bone fractures in confined regions. The above bone clamps, however, utilize a screw mechanism to tighten the jaws of the clamp for reduction of the fractured bone held therebetween. As a result, the reduction procedure cannot be performed with the speed permitted by use of a ratchet mechanism, nor is power delivered as efficiently and easily. In addition, the screw mechanism often requires the use of both hands, whereas the use of only one hand is preferable.